The invention concerns a device for the treatment of substrates comprising a container filled with a treatment fluid, wherein the treatment fluid streams in from below through the container bottom.
Devices of the aforementioned kind have been known, for instance, from DE 44 13 077 A1 and DE 195 46 990 A1 of the applicant of this present patent application and are also described in the German patent applications DE 195 37 879.2, DE 196 16 402.8, DE 196 15 969.5 or DE 196 37 875.3 of the same applicant, which have not been published as of the filing date of this application. Devices of the aforementioned kind have been successfully used in practice. However, they require a relatively high volume of costly, environmentally harmful and difficult-to-recycle treatment fluid. Furthermore, the requirement exists to provide flow conditions of the treatment fluid in the treatment container as steady as possible in order to treat the substrates to be processed, in particular during rinsing, homogeneously and uniformly across the entire substrate areas.
From the documents JP 3-266 431 A2 and JP 5-136 116 A2 devices of the aforementioned kind are known in which the container bottom is circular arc-shaped and matches the shape of circular discs. The device known from JP 7 249 604 A2 has a container bottom matching the shape of a cassette, wherein the cassette during fluid treatment is arranged in the cassette. The fluid in this known device is not introduced from below through the container bottom. The container bottom only has outlet openings through which the fluid content in the container is drained. From U.S. Pat. No. 5 071 488 and JP 6-252 120 A2 devices with a fluid inlet from below are known in which the wafers during treatment are arranged in a cassette and the fluid flows out via an outlet at the upper end of the fluid container. From JP 4-267 981 A2a device of the aforementioned kind is known which comprises a venting tube that is in communication with an inlet area below the actual fluid container and serves to remove air bubbles that may be present within the supplied hot clean water.
From U.S. Pat. No. 5 014 727, JP 7-106 295 A2 and JP 5-259 143 A2 devices of the aforementioned kind are known in which the fluid to be introduced is distributed below the container bottom into different distribution channels or tubes. JP 6-195 466 A2 shows a cleaning tank in which the cleaning liquid is introduced into the cleaning tank from below through slots arranged in the direction of the wafer edges. In the substrate treatment device known from JP 5-232 978 A2 the container bottom is comprised of a plurality of stacked plates having openings embodied such that the treatment fluid introduced from below is distributed to a plurality of outlet openings.
Based on this, the object of the invention is the development of a device of the aforementioned kind that provides an optimized treatment uniformly across the entire substrate areas with a minimum of design and manufacturing expenditures and with the minimum volume of treatment fluid possible.
The object of the invention is solved by providing at least two inlet tubes for the treatment fluid under the container bottom, wherein each is comprised of projecting comb-like meshing distribution channels. Such a fluid distribution system under the container bottom allows a steady inlet flow of the fluid and, thus, a homogeneous treatment of the substrates through the fluid regardless of the substrate area, i.e., regardless of the positioning of the substrate areas in the vicinity of the container walls or not. The comb-like distribution channels of at least one inlet tube are advantageously projecting perpendicularly therefrom and are advantageously positioned at the same level, wherein it is especially advantageous to position one distribution channel of an inlet tube respectively between two distribution channels of the other inlet tube. In this manner, the distribution channels of one level are alternatingly supplied with treatment fluid from different sides via the inlet tubes, resulting in a balanced discharged fluid volume and pressure across the entire area, providing a generally steady fluid introduction into the fluid container across the entire container area.
According to an advantageous embodiment of the invention, not only the distribution tubes are provided with outlet openings, but also the inlet tubes from which the distribution channels are projecting, thus providing a diffusor system with steady outlet flow conditions for the treatment fluid across the entire bottom area of the container. The inlet and/or distribution tubes may, in addition to a round embodiment, be of a rectangular, flat or square shape also. The size, shape and number of the openings in the inlet and distribution channels as well as their spacing to each other may be selected according to the respective conditions and, in particular, in regard of providing an inlet flow with generally the same fluid volume and the same fluid pressure per surface unit across the entire diffusor area.
According to an advantageous embodiment of the invention, the cross section surfaces of the inlet tubes and/or distribution channels are decreasing from the inlet location towards the end of the tubes, particularly advantageously as a conical embodiment, thus helping to achieve homogeneous pressure conditions and outlet flow volumes of the treatment fluid across the entire diffusor area.
In addition or independently from the inlet flow systems or the shape of the container bottom mentioned above, the object of the invention is also inventively solved by providing inlet flow slots extending parallel to each other under the container bottom in the inlet flow area of the treatment fluid. These inlet flow slots advantageously extend in the same direction as the edges of the substrates to be treated and serve as compensators for the inlet flow of the treatment fluid. These inlet flow slots are advantageously positioned between an inlet flow system, for example, a diffusor system with comb-like arranged distribution channels described previously, positioned underneath the container bottom. An additional effect is that in the case of a round embodiment of the container bottom, these inlet flow slots compensate and/or bridge the spacing between the inlet openings and the diffusor system positioned in one level. Based on these inlet flow slots, steady, optimized flow conditions within the fluid container can be achieved also in regard to the orientation of the wafer axis. It is especially advantageous, when the spacing of the inlet flow slots corresponds to the spacing of substrates in the container. In this manner, the treatment fluid is flowing controlled and directed between the substrates positioned parallel and with a certain spacing to each other, thus providing a more homogeneous optimized application of treatment fluid to the substrate surfaces.
To improve the fluid separation edges and the outlet flow conditions of the fluid at the outlet openings of the slots in general, it is advantageously suggested to embody these openings in the outlet area like a jet.
Advantageously, the inlet flow slots or other inlet openings, for example additional jets, in the area of a substrate carrier are embodied and arranged such that the treatment fluid in the container area is diverted around and above the substrate carrier. This is also possible with accordingly embodied guiding elements. This embodiment prevents dead flow angles that may occur around the substrate carrier. To avoid repetition concerning this embodiment, DE196 44 253 of the same applicant with the same application date is incorporated by reference into the present patent application.
Additionally or alternatively to the features mentioned above, the object of the invention is inventively solved by providing integrally embodied inlet openings for the treatment fluid in the container bottom. The container bottom is hereby advantageously embodied integrally such that the inlet openings are embodied also in the shape of inlet jets with optimized features. The container bottom is manufactured as a completed assembly with inlet openings or jets already integrated, with no assembly required, i.e., the inlet jets do not have to be assembled and installed into the container bottom, as this was the case, for instance, in the embodiment of DE 196 16 402 of the same applicant, which has not been published as of the filing date of this application. Significant assembly costs and considerable adjustment procedures are eliminated and no steps for the machining of threads and other parts for jets are required. It is especially advantageous that inlet openings as well as supply lines for these openings can be designed so as to have significantly less volume, thus keeping openings and cavities to a minimum and reliably preventing unnecessary fluid volumes and, in particular, development and accumulation of bubbles. Furthermore, the embodiment and arrangement of the inlet openings and jets may be optimized regarding their shape and size according to their respective position in the container bottom, providing an especially homogeneous flow distribution within the container. The embodiment and/or arrangement of the jets in the container bottom can be provided without subsequent adjustments.
According to an especially advantageous embodiment of the invention, the container bottom is comprised of integrated fluid channels for the supply of the inlet openings with treatment fluid. According to this feature, the fluid channels within the container bottom that are supplying the inlet openings with fluid, are integrally embodied. They do not have to be installed or assembled. In this manner, it is in particular possible to optimally adapt the fluid channels, their arrangement and diameter according to the inlet openings, thus preventing dead cavities or separation edges that otherwise would cause areas with inefficient flow and development of bubbles.
The container bottom including the embodied inlet openings, for instance inlet jets or holes, and/or the embodied fluid channels as well, are advantageously manufactured by injection molding. Another advantageous embodiment of the invention comprises manufacturing of the container bottom with integrated inlet openings and channels utilizing laser lithography technology.
According to another advantageous embodiment of the invention, the container bottom comprises a connection channel for introducing treatment fluid into the container bottom. In this manner, the container bottom is provided with an integrated inner thread, advantageously in the connection area, to which the treatment fluid line is attached or threaded. This feature also contributes to a uniform, single-piece container bottom arrangement and is easy to manufacture.
According to another very advantageous embodiment of the invention, the connection channel is divided into several segments, preferably four, at the inlet of the container bottom. According to another advantageous embodiment of the invention, several channel arms branch off, preferably correlated with the individual separate segments. In this manner, a fluid distribution system within the container bottom can be easily achieved and optimized in respect to the applications. In this context it is advantageous, when the cross section of the channel arms is decreasing towards the channel outlet, thus providing, as previously described, homogeneous pressure distribution across the channel arms.
According to a further solution of the object of the invention, an optimal and uniform treatment across the entire substrate surface and at all substrate locations is to be achieved and this is possible when advantageously the bubbles, that are contained in the treatment fluid or develop during introduction of the treatment fluid, are guided into venting channels or grooves provided therefor. Bubbles adversely affect the treatment of the substrates, for example, by causing an irregular application of treatment fluid, for example, a rinsing agent, to the substrates or by adhering temporarily to the surface of the substrates, thus preventing the homogeneous treatment of all substrate areas with treatment fluid. Advantageously, the venting channels or grooves are provided along the side walls of the container and, in particular, along the container walls extending perpendicularly to the substrate surfaces. The bubbles are collected in these channels, so that the actual treatment fluid which contacts the substrates to be processed is largely free of bubbles.
In case of a round or circular arc-shaped cross section embodiment of the container bottom, the venting channels are provided in the upper area of the laterally ascending container bottom.
It is especially advantageous when the shape of the container bottom matches the shape of the substrates to be processed. In this manner, unnecessary volumes within the container are eliminated, thus minimizing the fluid volume and improving the flow conditions within the container, in particular around the substrates, providing a more homogeneous flow distribution and more uniform treatment of the substrates across the entire substrate areas. To this end, it is not only possible to reduce the required volume of costly treatment fluid, but also to reduce the necessary amount of time for the treatment steps with the same results, for example during a rinse cycle, because less treatment fluid has to be introduced into the container or discharged from the container. Furthermore, by adapting the shape of the container bottom to the shape of the substrates, the flow conditions within the container and thus the treatment results, for instance by providing a homogeneous rinse of the substrates, can also be improved.
For disk-shaped substrates, for example, for the treatment of disk-shaped wafers, CDs or CD-ROMs as well as disk-shaped masks or LED display devices, a round or circular embodiment of the container bottom cross section is in particular advantageous. The embodiment of the round container bottom is advantageously provided concentric to the disk-shaped substrates. In this manner, dead areas or container and volume areas that are not required for the treatment of substrates are eliminated. The arrangement of the inlet openings along the round container bottom in comparison to conventional fluid containers with a flat or somewhat slanted container bottom can be optimized, thus providing homogeneous flow conditions within the fluid container.
This device for treatment of substrates can be used for all types of substrates. The term substrates comprises not only wafers, CDs, CD-ROMs, masks or LED display devices, but all objects or parts that may be subjected to a surface treatment, rinsing or drying process.